Review Article: Granulomatous Diseases and Granulomas of the Appendix

Abstract

Granulomatous appendicitis is a rare phenomenon. Idiopathic (primary) granulomatous appendicitis is very rare. It is a diagnosis by exclusion. There are many etiologies, both infectious and noninfectious, for secondary granulomatous appendicitis. Isolated appendiceal Crohn's disease (CD) is no longer an accepted explanation of idiopathic granulomatous appendicitis, but rather, it is thought to be part of more generalized gastrointestinal CD. Yersinia infection and CD constitute the main etiology of granulomatous appendicitis in the West. Infectious causes, mainly tuberculosis and parasitic infestations, are the main culprits in tropical and subtropical countries. This variation is probably a result of differences in the geographical distribution of these diseases. Recently, interval appendectomy has been suggested as an important cause of granulomatous appendicitis. The importance of interval appendectomy may vary according to the local practice of this procedure in each region. Other unusual causes may include sarcoidosis and foreign body reaction, mainly as a result of vegetable matter from feces. A review study of 3381 appendectomy specimens over a 4-year period showed only 13 cases (0.38%) of granulomatous appendicitis. Infectious and noninfectious causes were responsible for 62% and 38% of granulomatous appendicitis, respectively. Parasites alone were responsible for 38.5% of the cases. Interval appendectomy and CD each contributed 15% and 8%, respectively, of the total etiology. Granulomatous appendicitis was more common in young adult males.